Conversion Efficiency Of DSSC Research Articles

Studies in the influence of D–π–A pyrenyl chalcone containing methoxy substitution as dye-sensitizer in DSSC

A pyrene based chalcone (PyMe) has been prepared by Claisen-Schmidt condensation reaction. The proposed structure was proceeded for characterization analysis of Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopic (FTIR) and Ultraviolet-Visible (UV-Vis) studies. The analysis of cyclic voltammetry (CV) performed has determined the appropriated position of HOMO and LUMO energy level for electron injection and dye regeneration in DSSC. The Field-Emission Scanning Electron Microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDX) study has confirmed the existence of PyMe based on the distribution and composition of the elements on the TiO2 layer, respectively. The Donor–π–Acceptor (D–π–A) structural chromophores with methoxy (-OCH3) attachment in PyMe has also contribute to the power conversion efficiency of DSSC.

Boosting dye-sensitized solar cell efficiency using AgVO3-doped TiO2 active layer

Dye-sensitized solar cells have shown great potential in low and self-powered nano/micro-scale applications, due to their low fabrication costs, semi-transparency in the visible spectrum, diffused light harvesting capabilities, and their lead-free structure. However, DSSC efficiencies are still relatively low due to their limited absorption capabilities in the active mesoporous layer. The current study demonstrates an attempt to boost the overall conversion efficiency of DSSC by narrowing the energy band gap of the mesoporous TiO2 active layer. AgVO3 is utilized in doping the mesoporous layer, seeking for a visible absorption shift from 3.2 eV to 2.6 eV. In addition, natural organic beetroot dye is used while keeping DSSC with N719 dye as a bare cell. Morphological, optical, as well as electrical characterization results were obtained for both thin-film and complete solar cells. The fabricated cell showed an overall harvested power density of 8.6 mW/cm2, capable of operating various low-power sensing applications.

Design of novel substituted phthalocyanines; synthesis and fluorescence, DFT, photovoltaic properties.

The 4-(2-[3,4-dimethoxyphenoxy] phenoxy) phthalonitrile was synthesized as the starting material of new syntheses. Zinc, copper, and cobalt phthalocyanines were achieved by reaction of starting compound with Zn(CH3COO)2, CuCl2, and CoCl2 metal salts. Basic spectroscopic methods such as nuclear magnetic resonance electronic absorption, mass and infrared spectrometry were used in the structural characterization of the compounds. Absorption, excitation, and emission measurements of the fluorescence zinc phthalocyanine compound were also investigated in THF. Then, structural, energy, and electronic properties for synthesized metallophthalocyanines were determined by quantum chemical calculations, including the DFT method. The bandgap of HOMO and LUMO was determined to be chemically active. Global reactivity (I, A, η, s, μ, χ, ω) and nonlinear properties were studied. In addition, molecular electrostatic potential (MEP) maps were drawn to identify potential reactive regions of metallophthalocyanine (M-Pc) compounds. Photovoltaic performances of phthalocyanine compounds for dye sensitive solar cells were investigated. The solar conversion efficiency of DSSC based on copper, zinc, and cobalt phthalocyanine compounds was 1.69%, 1.35%, and 1.54%, respectively. The compounds have good solubility and show nonlinear optical properties. Zinc phthalocyanine gave fluorescence emission.

Fabrication Rutile-Phased TiO2 Film with Different Concentration of Hydrochloric Acid Towards the Performance of Dye-Sensitized Solar Cell

In this study, one-step hydrothermal method is demonstrated to synthesis TiO2 double-layer structure by modifying the concentration of hydrochloric acid (HCl). The X-ray diffraction (XRD) pattern analysis suggested that the dominant peak is rutile phase. Interesting morphologies such as cauliflower, chrysanthemum flower or dandelionstructures over the nanorods layer were revealed by FE-SEM images and showed substantial effects to the thin film performance. UV-vis absorption spectra of prepared TiO2 film is in UV limitation with band gap energy (Eg) range from 2.57eV to 3.0eV. The optimum photoelectric conversion efficiency of DSSC is 42.5% that exhibited the efficiency of 6.41% for the sample synthesized using equal proportion of de-ionized water and HCl amount or in another word in accordance of ratio 1:1. These results serve as a guidance principle for preparing high quality DSSC thin film.

The Impact of PDDA in CNT Counter Electrode on the Conversion Efficiency of DSSC

The Impact of PDDA in CNT Counter Electrode on the Conversion Efficiency of DSSC

Performance of Strelitzia reginae Flowers Dye as Sensitizer for New Dye-Sensitized Solar Cell Fabrication

In current study, the dye from flowers petals of Strelitzia reginae used for the first time to prepare natural photosensitizer for DSSC fabrication. Among five different solvents used to extract the natural dye from S. reginae flowers, the ethanol extract of anthocyanin dye revealed higher absorption spectrum of 0.757a.u. at wavelength of 454nm. A major effect of temperature was studied to increase the extraction yield. The results show that the optimal temperature was 70 °C and there was a sharp decrease of dye concentration from 0.827 at temperature of 70 °C to 0.521 at temperature of 90°C. The extract solution of flowers of S. reginae showed higher concentration in acidic media, especially at pH 4 (0.902). The C, H, N elemental analyses of natural extract showed the presence of N (10.52%), C (18.97%) and H (2.229%) contents. The presence of anthocyanin in the extract of S. reginae and their functional groups were determined using UV-Vis spectroscopy and Fourier-Transform Infrared Spectroscopy (FTIR). The optical properties of deposited TiO2 thin film were studied using scanning electron microscope (SEM) and X-Ray Diffraction (XRD). In Addition, other confirmation that dye supported surface of TiO2, inhibition of crystallinity of TiO2 was investigated by the Energy Disperse X-ray (EDX) analysis. According to experimental results, the conversion efficiency of DSSC fabricated using anthocyanin dye obtained from S. reginae flowers was 0.1%, with short-circuit current (Isc) of 0.6 mA/cm-2, open-circuit voltage (Voc) of 0.51 V and fill factor (FF) of 36.83%.

Synergistic effect of sodium and yeast in improving the efficiency of DSSC sensitized with extract from petals of Kigelia Africana

TiO2 nanostructures with two different dopants, sodium and yeast have been successfully synthesized by hydrothermal method. Doping sodium is found to extend the absorbance of TiO2 into the visible region as well as it acts as mordant in fixing and improving the absorption of dye. Yeast, as a dopant, can help in absorption of more anthocyanins from the natural dye extract by TiO2 and also aids in retaining the colour of the dye and increases the stability of the dye at varying pH. Anthocyanins are the major class of pigment present in the newly addressed maroon, velvety and trumpet shaped flower “Kigelia Africana”. X-ray diffraction analysis revealed the formation of rutile phase for all the samples. Field Emission Scanning Electron microscopy images revealed the formation of nanorods and nanoflowers with change in dopant as well as their concentration. The photoelectric conversion efficiency of DSSC with undoped TiO2 photoelectrode is 0.87% and DSSC with 6% Na doped TiO2 photoelectrode is 1.56%. The efficiency of DSSC with 6% Na+6% yeast doped TiO2 photoelectrode is found to increase from 2.09% (DSSC with 6% Na+4% yeast doped TiO2 photoelectrode) to 2.31% on varying the dopant concentration. Doping is also found to increase the dye absorption and superior charge transport efficiency which in turn helps to improve the performance of DSSC.

Studies on DSSC encompassing flower shaped assembly of Na-doped TiO2 nanorods sensitized with extract from petals of Kigelia Africana

Flower of Kigelia Africana constitute anthoyanin as a predominant flavonoid pigment and are responsible for absorption of light in visible region. In the present study, the extract of this flower is used as sensitizer for DSSC. Na-doped TiO2 nanorods have been synthesized via one step hydrothermal method and used as photoanode. XRD analysis of Na-doped TiO2 nanorod samples revealed the formation of single rutile phase structure. FESEM images revealed the formation of nanorods and overgrowth of nanoflowers on increasing the amount of the dopant. The photoelectric conversion efficiency of DSSC increased from 1.09% to 1.56% when compared to undoped TiO2 based DSSC that exhibited an efficiency of 0.87%. A relatively high open circuit voltage was obtained because of nanorods structure and doping technique. The downward shift of flat band voltage with Na-doped TiO2 improved the driving force for electron injection, leading to the enhanced photocurrent density.

Fabrication, characterization and comparison of DSSC using anatase TiO2 synthesized by various methods

In this study, anatase TiO2 nanoparticles were synthesized by three techniques, namely, sol–gel, acid-base co-catalyst and room temperature colloidal methods. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, pore diameter, pore volume and surface area. The dye-sensitized solar cells were fabricated using the synthesized materials and characterized for incident photon to current conversion efficiency, photocurrent density to photo voltage measurement and electrochemical impedance analysis. Among the studied materials, TiO2 synthesized by sol–gel method displayed highest photon to current conversion of 76.8% and a maximum solar cell efficiency of 7.85% with Jsc of 14.75mA/cm2, Voc of 0.76V and FF of 0.7. This is the first study to report a high power conversion efficiency of DSSC using a sol–gel synthesized titania and its comparison with other two synthesized materials. The high power conversion efficiency of the solar cell using TiO2 synthesized by sol–gel method is attributed to its characteristic properties such high surface area, larger pore diameter and larger pore volume and highest dye loading capacity.

The Effect of FTO Sheet Resistance on the Efficiency of Dye Sensitized Solar Cell

In this work, DSSCs have been fabricated successfully using a simpleprocedure without the need for any complicated facilities. The XRD analysis of theTiO2 film confirmed that it has a polycrystalline structure belonging to anatasephase with crystallite size of 12.4 nm. UV-Vis spectroscopy was used tocharacterize the absorbance spectrum of the TiO2 film and Z907 dye. The energygap of the TiO2 film estimated by Tauc’s plot was 3.12 eV. The SEM micrograph ofthe TiO2 film shows that the layer has a spongy shape with reduction in the numberof open pores making easy for dye adsorption and electron transport. The AFMmicrograph and the granularity cumulative distribution chart of the TiO2 film showsthat the average roughness, root mean square roughness and average grain sizewere about 0.356 nm, 0.423 nm and 82.48 nm respectively. The DSSC fabricatedusing glass substrates coated with 8 Ω/ sheet resistance FTO achieved the highestshort circuit density (JSC) and conversion efficiency (η) of 4.069 mA/cm2and1.786 %, respectively. Subsequently, the enhancement in efficiency was ~ 84 %compared with the conversion efficiency of DSSC fabricated using glass substratescoated with 15 Ω/ sheet resistance FTO.

Construction and Optimization of the Dye Sensitization Solar Cell Using a Au Particle and a Natural Vegetable Pigment

Au nanoparticles dispersion liquid and the pokeweed pigment solution respectively showed the maximum absorption wavelength at visible region by UV-vis absorption spectrum. The conversion efficiency of DSSC which was assembled with Au+TiO2 film and TiO2 film was respectively 0.0529 % and 0.0167 %. The difference in this conversion efficiency depends on magnitude relation of the short circuit photocurrent density. Charge transfer resistance decreases by adding the Au nanoparticles which are a metal to TiO2 which is a semiconductor, and it is thought that short circuit photocurrent density increased. In addition, it is thought that this is because the excitation of the pigment became easy to happen by reinforced light electric field occurred by the plasmon absorption of metal nanoparticles. The improvement of the conversion efficiency was confirmed, but performance is largely low in comparison with general DSSC. Using ac impedance measurement, the resistance ingredient in the cell is identified.

Enhancing power conversion efficiency of DSSC by doping SiO2 in TiO2 photo anodes

A simple, less time consuming, cost ineffective sol–gel method was used to synthesis TiO2 nanoparticles (TiO2) and TiO2–SiO2 nanocomposites (TiO2–SiO2) using titanium tetra isopropoxide as TiO2 and silicic acid as SiO2 precursors respectively. The synthesized nanocomposites were characterized by XRD, SEM, TEM, UV–visible, FTIR and BET analysis. The quantum confinement effect of TiO2 and TiO2–SiO2 was confirmed by a blueshift observed in UV–visible spectra. The band observed at 950cm−1 in FTIR analysis confirmed the presence of Ti–O–Si bonds, the TEM analysis shows both the TiO2 and TiO2–SiO2 were in nanometer size. The BET (Brunauer– Emmett–Teller) specific surface areas of the samples were 65 and 75m2/g for TiO2 and TiO2–SiO2 respectively. The power conversion efficiency (PCE) of the nanocomposites were studied by using Keithely electrometer and multimeter and it was found to be 2% and 2.5% for eosin-Y sensitized TiO2 and TiO2–SiO2 nanocomposites respectively.

J-Aggregates of Amphiphilic Cyanine Dyes for Dye-Sensitized Solar Cells: A Combination between Computational Chemistry and Experimental Device Physics

We report on the design and structure principles of 5,5′-6,6′-tetrachloro-1,1′-dioctyl-3,3′-bis-(3-carboxypropyl)-benzimidacarbocyanine (Dye 1). Such metal-free amphiphilic cyanine dyes have many applications in dye-sensitized solar cells. AFM surface topographic investigation of amphiphilic molecules of Dye 1 adsorbed on TiO2anode reveals the ability of spontaneous self-organization into highly ordered aggregates of fiber-like structure. These aggregates are known to exhibit outstanding optical properties of J-aggregates, namely, efficient exciton coupling and fast exciton energy migration, which are essential for building up artificial light harvesting to the photovoltaic device. A light-to-electricity conversion efficiency of DSSC based on the metal free amphiphilic Dye 1 isη=3.75, which is about 50% of that based on metal-based N719 Ru-dye (Di-tetrabutylammoniumcis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II)). DFT and TD-DFT studies show that large intramolecular charge transfer takes place from the HOMO to LUMO. HOMO is localized on a part of the molecule with almost no contribution from the carboxylic moiety. This clearly indicates that the anchoring carboxylic group plays a minor role.

Improved electrochemical performance of dye-sensitized solar cell via surface modifications of the working electrode by electrodeposition

Modifications of the working electrode with TiO2 blocking or coating layers are carried by electrodeposi- tion in TiCl3 precursor solution. The results suggest that the electrodeposited TiO2 blocking layer provides excellent agglutination between the FTO substrate and the active TiO2 layer. In addition, the electrodeposited TiO2 coating layer enhances the interconnections between the TiO2 nanoparticles and the FTO substrate, and therefore it increases the electron transport efficiency. The morphology and crystalline structure of the electrodeposited TiO2 layers are char- acterized by SEM, TEM, and XRD. The electrochemical impedance spectroscopy measurements show that the improved DSSC performance with the electrodeposited coating layer is mainly due to the increase in the lifetime of the conduction band electron in the TiO2 film. The photoelectron conversion efficiency of DSSC is increased from 3.47% to 5.38% by employing the TiO2 electrodeposited working electrode. � /I3 � ) redox electrolyte, and a platinum-coated transparent conducting oxide (TCO) glass as a counter electrode. The electrons excited from the dye are transferred step by step through the conducting band of TiO2 nanoc- rystallites and FTO electrode. The dye is regenerated by electron donation from the redox system of the electrolyte. The iodide is re- covered by the reduction of triiodide on the platinum layer of the counter electrode. In practice, the FTO surface might not be fully covered with the mesoporous TiO2 film due to the porous nature of the TiO2 film. The exposed surface area of the FTO to the electro- lyte may lead to charge recombination between the TiO2 and the FTO interfaces. Electron transfer to the FTO is possibly intercepted by the reduction of the electrolyte interacting with the electrode. Another weakness of mesoporous TiO2 films is the inadequate con- nection between TiO2 nanoparticles, leading to an increase in elec- tron transfer resistance (6-8). To solve this recombination and elec- tron transfer resistance problem, previous studies have demonstrated that it is effective to introduce a compact and thin TiO2 blocking layer onto the transparent conducting glass substrate (9-11) using a range of preparation methods such as sputtering (11,12), sol-gel (13, 14), and spray-coating (15,16) techniques. A TiCl4 post-treatment of the TiO2 photoanode is a common modification method for ob- taining a reliable thin TiO2 coating layer to improve the cell perfor- mance such as current density, fill factor, and conversion efficiency (17-19). In this study, an electrodeposition strategy was used to modify the mesoporous TiO2 photoanode in two schemes: i) a blocking layer prepared first by the electrodeposition on the FTO substrate and then TiO2 photoanode fabricated, and ii) a TiO2 photoanode fabri- cated first and then the electrodeposition performed for covering the interfaces on the FTO substrate and mesopores between TiO2 nanoparticles. Experimental parameters for TiO2 electrodeposition were applied voltage and electrodeposition time. The blocking layer can reduce the electron recombination phenomena from FTO to electrolyte by separating effectively at a specific layer thickness (20). In addition, a thin TiO2 coating layer formed by the electrodeposi- tion can not only reduce electron recombination from FTO to elec- trolyte, but also increase electron transport between TiO2 nanoparticles because the TiCl3 precursor solution can penetrate deep into the ex- posed FTO surface and the mesoporous TiO2 nanoparticles. The photovoltaic properties of the DSSCs with the TiO2 modified photo anode by electrodeposition were characterized and compared with those of the unmodified photo anode case.

Preparation of TiO2 nanoparticles by using tripodal tetraamine ligands as complexing agent via two-step sol–gel method and their application in dye-sensitized solar cells

The effect of different tripodal tetraamine ligands was investigated on the particle size, agglomeration level, optical and photovoltaic properties of TiO2 nanoparticle prepared via a two-step sol–gel method. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron spectroscopy (TEM), scanning electron microscopy (SEM), and UV–vis spectroscopy. The results showed that the symmetry of ligands has a crucial effect on the size and agglomeration level of the products. The optical and photovoltaic properties of the products were studied, as well. The reflectivity property of the samples due to different agglomeration sizes is shown to be very important factor in increasing conversion efficiency of DSSC.

Effects of Iodine Content in the Electrolyte on the Charge Transfer and Power Conversion Efficiency of Dye-Sensitized Solar Cells under Low Light Intensities

This paper presents a systematic investigation on the effects of iodine content in the electrolyte on electron recombination, charge, and ion transportation to the power conversion performance of dye-sensitized solar cells under lower light intensities. By analyzing the current–voltage behavior and electrochemical impedance spectroscopy results, the effects of iodine content on charge recombination, ion transportation, and light intensity are found to be the major factors. The power conversion efficiency of DSSC under low light intensity can be significantly improved when electrolyte composition is optimized, which results in an exclusive application for indoor use.

Synthesis of Rare Earth Up-Conversion Material and Application in the Dye-Sensitized Solar Cells

Er3+ ,Yb3+ :Y2O3 nanocrystal up-conversion material has been prepared using the sodium carbonate precursor method and doped in the P25 to prepare up-conversion nano-TiO2 powder. The micromorphology, structure and particle size of the up-converting nanoparticles were characterized by atom force microscopy (AFM) and X-ray diffraction (XRD). Nano-TiO2 powder with up-conversion performance was applied to Dye-sensitized solar cells, the photoelectric conversion efficiency of the DSSC with up-conversion material is twice the photoelectric conversion efficiency of normal DSSC irradiated by infrared light.

Characterization of Nano-sized ZnO Electrodes with Curcumin-derived Natural Dye Extract for DSSC Application

Zinc oxide (ZnO) powder was first prepared by hydrothermal synthesis at low temperature. X-ray diffraction (XRD) investigation was carried out to examine the structural properties of ZnO powder. ZnO colloidal solution was deposited onto ITO/glass by rolling. After air drying, annealing in O2, atmospheric ambient was performed at 300 C and 400 C for 1 h. As the surface treatment, sintered ZnO film was immersed in 0.1 M HCl, washed with DIW and dried at room temperature. The Curcumin, a yellow-orange dye found in turmeric root, was used as a photosensitizer and was carefully prepared to avoid colour fading. Next, the ZnO film was dipped in dye solution for 15 h. High performance carbon counter electrode was prepared and used as a counter electrode. Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic response of ZnO cell was measured and it was expected to utilize the DSSC application. The conversion efficiency of DSSC at 400oC (0.129%) was found to be larger than that of the cell at 300oC (0.117%).

Synthesis of TiO2 Nanotube by Hydrothermal Method and Application for Dye-Sensitized Solar Cell

The TiO2 nanotube was synthesized by a hydrothermal method dependent on temperature. TiO2 nanotube was coated on FTO glass by screen printing The TiO2 nanotube was increasing as autoclaving temperature. The dye-sensitized solar cells were fabricated using ruthenium (II)(N719) dye and electrolyte (). The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The absorption spectra were measured by UV-vis spectrometer. The conversion efficiency was measured by solar simulator. The size and structure of TiO2 nanotube were adjusted by hydrothermal temperatures. It was found that the conversion efficiency of DSSC was highly affected by the properties of TNT. The diameter of the TiO2 particles depends on the different hydrothermal temperatures.

Influence of Donor Moiety in Ruthenium Sensitizers on the Properties of Dye-Sensitized Solar Cells

Heteroleptic ruthenium complexes cis-[Ru(H2dcbpy)(L)(NCS)2], where H2dcbpy is 4,4'-dicarboxylic acid-2,2'-bipyridine and L is 4-(4-(N,N-di-(p-hexyloxyphenyl)-amino)styryl)-4'-methyl-2,2'-bipyridine (Rut-A) or 4-(4'-(3,6-dihexyloxycarbazole-9-yl)-styryl)-4'-methyl-2,2'-bipyridine (Rut-B), have been synthesized and characterized by NMR, UV-Vis spectroscopy, and cyclic voltammogram. The effect of different electron donors on the properties of dye-sensitized solar cells has been studied. The power conversion efficiency of DSSC based on Rut-B is 6.1% while Rut-A delivered a lower efficiency of 4.52% under the same device fabrication and measuring conditions. The better photovoltaic performance of Rut-B is mainly associated with enhanced dye absorptivity and charge recombination suppression.